Before this change, building Neovim would recursively search parent
directories for a .git directory. If Neovim was downloaded as a tarball
(i.e. without a .git directory), but placed in a subdirectory of
a Git repository, this caused a CMake error. Such a situation could
occur when packaging Neovim, for example.
Unfortunately, the previous attempt in #3317 did not fix this problem.
- cmake: git_timestamp() returns last commit time formatted as
`YYYYMMddHHmm`.
- Always include commit hash in :version and --version output.
`nvim --version` sample output:
NVIM 0.0.0-alpha+201410070245 (compiled Oct 7 2014 05:30:45)
Commit: f747b2b1ff7bfe7eb00cc2be82d7af87c98f1111